Good advice on using the NFPA formulas Travis, thanks, and when I am 'on the clock' I do. Thanks John. I didn't care during my first twenty years. But I always had an uneasy feeling when "everything I know about hydraulics I learned from the rules in NFPA 13". Unlike you, I was an English Major when I dropped out of college. Now this question is merely an after-hour curiosity, for entertainment purposes only if you will. That FM 2 1/2" K looks like C=.8 Allan, thanks.
Brad On Feb 22, 2017 11:42 PM, "IPA" <[email protected]> wrote: > I believe I saved this info from this very forum but I have noted that FM > global used to have k-factors for hydrants. Here are the values: > 2 3/8" 134 > 2 1/2" 149 > 2 5/8" 164 > > On Wed, Feb 22, 2017 at 6:48 PM, John Denhardt < > [email protected]> wrote: > >> Travis - well said >> >> Brad - who really cares if hydrants have a K factor? I know I don't. >> >> John August Denhardt, P.E. >> Strickland Fire Protection >> >> On Feb 22, 2017, at 8:45 PM, Travis Mack, SET <[email protected]> >> wrote: >> >> Or just use the formula in NFPA 291- Standard for Hydrant Marking and >> flow tests or something like that... >> >> Q = 29.83*d^2*Cd*P^0.5 >> >> d = hydrant outlet diameter in inches >> >> C = the outlet coefficient (0.7, 0.8 or 0.9) >> >> P = Pitot pressure that is measured >> >> Not everything has to be extremely complicated and thought out to the nth >> degree. If you are really so inclined, why not spend the next few years >> solving for Pi to the 1,000,000th point. And guess what...... if you >> assign K to be 29.83*d^2*Cd........ you get 168 for your example. >> Wow...sometimes the simplest methods are the best. >> >> There is a true phenomenon that causes many people problems - *paralysis >> through analysis*. >> >> >> Travis Mack, SET >> MFP Design, LLC >> 2508 E Lodgepole Drive >> Gilbert, AZ 85298480-505-9271 <(480)%20505-9271> >> fax: 866-430-6107 <(866)%20430-6107>email:[email protected] >> http://www.mfpdesign.comhttps://www.facebook.com/pages/MFP-Design-LLC/92218417692 >> Send large files to us via: https://www.hightail.com/u/MFPDesign >> LinkedIn: https://www.linkedin.com/in/travismack >> >> On 2/22/2017 5:58 PM, Brad Casterline wrote: >> >> Say it's a 2.5" C=.9. >> >> I've tried to work this out a couple different ways: >> 1) a kind of long drawn out way, call it 'brad's way', and I get ~168. >> 2) a way i call the 'Bill Brooks back of napkin' way based on a few words >> he posted here a few years ago-- lightening fast, and i'll be damned if i >> dont get the same ~168! Basically, since K is the square feet area of the >> orifice he says 5*5*5.6=140, times (.9/.75) = 168. >> Anyway, if a hydrant butt has a K we could pretty quickly get the Q after >> the pitot'd P with Q=K*SQRT(P). >> >> thanks, >> >> Brad >> . >> >> >> _______________________________________________ >> Sprinklerforum mailing >> [email protected]http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org >> >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum- >> firesprinkler.org >> >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum- >> firesprinkler.org >> >> > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler. > org > >
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